Thyssenkrupp Rasselstein now offers chromium-free passivation alternative

Thyssenkrupp Rasselstein is now offering its customers Rasselstein CFPA (Chromium-Free Passivation Alternative), a 100% chromium-free passivation based on titanium, for use on the surface of tinplate. This passivation alternative minimises the tin oxide growth during storage, providing the same functionality as chromium-based passivation.

CFPA is fully compliant with EU and FDA regulations and is approved both for coated as well as uncoated tinplate for contact with foodstuffs. European standard EN 10202 is currently being revised to incorporate CFPA as the new European standard passivation.

“For stability tests with a wide range of fillings, it is common to conduct not just laboratory tests, but also time-consuming storage tests lasting up to several years. Thyssenkrupp Rasselstein supports the entire value chain with the early provision of a chromium-free product. The tests can now begin if they have not already,” said Heiner Schäfgen, head of technical customer service at Thyssenkrupp in Andernach, Germany.

Rasselstein CFPA minimises the tin oxide growth during storage, providing the same functionality as chromium-based passivation. It gives tinplate high-quality surface properties, such as a brilliant appearance, best lacquer adhesion, excellent wettability, and very good direct printability.

Comprehensive tests have confirmed that suitable lacquer systems are available for existing application purposes. “Rasselstein CFPA works particularly well with modern BPA NI lacquers,” said Martin Schlupp, head of surface technology and chemistry at Thyssenkrupp. “CFPA has a higher surface tension than chromium-based passivations, which gives it a better wettability.”

“A number of Thyssenkrupp’s customers in Andernach have already made the changeover, while others are beginning the transition to a chromium-free future. We have received a great deal of positive feedback worldwide so far.

“The end of the authorisation period currently seems to be a long way off, but the deadline is approaching — and all can manufacturers will need to have made the change by then,” said Schäfgen.

“As part of the successive, irreversible conversion of our tinning lines from 2019 onwards, the market availability of tinplate with chromium-free passivation is continuously increasing. Customers must now consciously decide on a date from which deliveries of chrome-free passivised materials will take place. The majority of lacquer systems will work on them without any changes.

“In individual cases, adjustments will need to be made for established epoxy systems, but if a new BPA NI lacquer were to be introduced today, the systems would also need to be adjusted, as is the case with the use of tinplate with the innovative CFPA surface — hence, it is not a ‘new unknown’.”

When transitioning to Rasselstein CFPA, customers of Thyssenkrupp can rely on the full support of technical customer service, which will advise them on all issues.

“Furthermore, the network of lacquer suppliers, packaging steel manufacturers, packaging manufacturers and fillers we have established ensures that the transition to tinplate with chromium-free passivation takes place as smoothly as possible,” said Schäfgen. “Hence, the right framework for the transition already exists, as does the right time – which is right now.”

Regulation (EC) No 1907/2006 (also called the REACH Regulation) governs the EU-wide use of chemicals. It stipulates that chromium(VI) compounds, which to date have been used in the manufacturing of tinplate passivation, may only be used for a limited period of time. For manufacturers of packaging steel, this means that they will no longer be able to obtain chromium-passivated tinplate manufactured in the EU beyond this time.

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